Interpretive Summary: Since 1989, records from the Germplasm Evaluation project at the U.S. Meat Animal Research Center have been used to derive adjustment factors which allow comparison of the genetic merit of animals in different breeds. The factors are simply added to the expected progeny differences (EPDs) calculated by each breed association in individual analyses. For example, EPDs of a Charolais bull can be equitably compared to EPDs of a Gelbvieh bull by adding the respective breed adjustment factor to each bull’s EPD. The adjustment factors are useful to commercial producers who may wish to compare the genetic merit of bulls from more than one breed in crossbreeding programs. This report is presented at the annual meeting of the Beef Improvement Federation. Adjustment factors are calculated on growth and milk traits for 16 different breeds (Angus, Beefmaster, Brahman, Brangus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Maine-Anjou, Red Angus, Salers, Shorthorn, Simmental, South Devon, and Tarentaise). Results from the report are the basis for a press release containing the current across-breed adjustment factors and instructions on their use. This release is distributed to producers, farm magazines, the artificial insemination industry, and breed associations.

Technical Abstract:
Records of F1 and 3-way cross progeny of 16 breeds of sire and maternal grandsire, respectively, were used to estimate differences among the breeds for birth, weaning, and yearling weight and for maternal effects of weaning weight. The records were also used to estimate regression coefficients of progeny performance on breed association EPDs. The regression coefficients represent the proportion of the differences in sire EPDs that were exhibited in the progeny at USMARC and are used to adjust the breed differences estimated from USMARC data to the differences between animals in the breed born in 2005 (based on the 2005 breed average EPD). Using these adjusted breed differences, adjustment factors were calculated that can be added to breed association EPDs to allow comparison of bulls from the 16 breeds (Angus, Beefmaster, Brahman, Brangus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Maine-Anjou, Red Angus, Salers, Shorthorn, Simmental, South Devon, and Tarentaise). This report details the calculations used for the annual update of the procedure first implemented in 1991. Changes for 2007 included the addition of progeny weights on 7 breeds and grandprogeny weights on 9 breeds. The methodology was also changed to convert the USMARC breed differences to the industry EPD scale.